Electric ignition apparatus for internal-combustion engines.



G. OOWGHER.

ELECTRIC IGNITION APPARATUS FOR INTERNAL COMBUSTION ENGINES.

APPLICATION TILED DEG. 23,1912.

Patented Jan. 26, 1915.

GEORGE oowcHEB, or WIMBLEDON, EmeLANn.

' ELEormc IGNITION arrnaa'rus FOR. INTERNAL-COMBUSTION ENGINES.

master.

Specification of Letters Patent.

Patentee 26,1915.

Application filed December 23, 1912. Serial N 0. 738,279.

T o all whom; it may concern Be it known thatI, GEORGE CowoHnR, asubject of the King of Great Britain, re-.

siding at Wimbledon, in the county of Surrey, England, has inventedcertain new and useful Improvements in Electric Ignition Apparatus for'Internal Combustion Engines, of which the following is a specification,reference being had therein to the accompanying drawing.

This invention relates to sparking plugs for internalcombustion enginesof that type where ahollow terminal is employed which forms anobservation tube or view piece to enable the spark and also the flame ofcombustion to be pected under worldng conditions of compressionandjfiring.

The invention consists primarily of a particular construction of suchsparking plugs which involves essentially an inner hollow v electrodeprovided with a transparent view some means for piece, an outer metallicbody or shell insulated from the inner hollow electrode, and

between the inner hollow electrode and the outer metallic body or shell.The plugs may be connected to the electrical leads in any suitablemanner either direct to the lead terminals or by means of adapters aswill hereafter be made clear;

To enable the invention to be more clearly v understood I will nowdescribe it with ref- .erence to the accompanying drawing Figure .-1 isa sectional elevation of a sparking plug constructed in accordance withmy invention. Fig. 2 is an under plan thereof. Fig. 3 is a sectionalView of a,

modified construction of sparking plug, and

- Fig. 4 is an underplan view thereof.

Referring to these drawings and particularly to Fi 1 and 2 the viewpiece 1 which is preferab y solid may be of any transparent substancecapable of withstanding heat and pressure, or of any shape such asspherical, cylindrical or any modification of such primary forms. Imount this view piece in a. hollow metal casing 2 with suitable packing.washers 3 to prevent the passage of the gases as well as to prevent itsbeing injured by the pressure attendant on the method of mounting.

The casing 2 should preferably be made of'a metal which is a goodconductor of electric current, notliable to corrode, or it may be madeof a cheaper material and fitted "By screwing down the nut providing afixed spark gap.

or the like. This casing 2 with its exten sion 4 forms what in ordinaryspark plugs corresponds to the central insulated wire or electrode.

- The numeral 5 designates an insulator.

preferably of porcelain or steatite, but not preferably of porcelain orsteatite, which incases the extension 4, the'one end of which insulatorabuts against a shoulder on the latter. 4

The numeral 9 designates a gland nut, which in turn abuts against ashoulder 10 formed on insulator 8. It is arranged in.

this case to screw on to the plug body 6. 9, pressure is ex-' ertedrendering the joints gastight through the medium of the packings beforementioned.

The casing 2 and its extension 4 maybe fitted together in contact asshown in Fig. 1.

It is very essential that proper'electric contact be assured betweenthese parts 2 and 4.

The spark plug body 6 is similar to those commonly in use and is formedwith a spigot 11 for screwing into the cylinder or valve' cap of themotor. It is fitted with.

sparking points 12 of some material which is not liable to corrode ormelt, such as nickel, platinum or the like. These points are to bearranged to give the proper sparking. distance between them and the vlectrode2 or a point or points aflixed to such electrode. 13 is a nut bywhich thelead terminal 14' is secured in position.

In Figs. 2 and 3 I have shown a slightly modified construction. In thiscase 15 is the casing containing the view piece 16. An extension 17proceeds from the casing 15 and is connected thereto by screwing as at17. Insulation packing rings 18 are provided as before. A singleinsulator 19 separates the casing 15 ande'xtension 17 which as beforeforms the hollow electrode, from the plug body 20, and a nut 21 screwinginto the plug body 20 forms the means of securing the parts together,packing rings 22 being provided to insure tight joints. The nut 23secures the lead terminal 24 between it and the nut 25 and this nut 23is provided with a second transparent View piece 26 which protects theview piece 16 from dust. Fixed spark points 27 cooperate with the casing15 to form the necessary spark gaps.

That I claim and desire to secure by Letters Patent is:

1. In a spark plug, an outer hollow body carrying spaced sparkingpoints, an insulator supported in the body, a central elec-' trodecomprising a hollow metal casing supported in the insulator, saidelectrode having shoulders, a transparent material supported by theshoulders, a screw threaded tube positioned in the electrode so that oneend thereof engages the transparent material, and means disposedadjacent the opposite end of the tube for protecting the transparentmaterial from'foreign substances.

2. in a spark plug, an outer hollow body carrying sparking points, aninsulator supported in the body, and a central electrode comprising ahollow metal casing supported in the insulator, means for supporting aview piece adjacent the sparking points and tubular member, one end ofthe tubular member adapted to engage the view piece, a nut on theopposite end of the tubular member, said nut having a recessed portion,and a guard supported in the recessed portion for protecting the viewpiece.

In testimony whereof I aflix mysignature in presence of two witnesses.

GEORGE COWCHER. f Witnesses:

EDWARD A. EVE, O. J. WORTH.

